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NS1000. DSP Resources. Contents. 1.1 Overview 1.2 DSP Resource Capacity 1.3 DSP Resource Usage 1.4 DSP Usage – Summary 2.1 DSP Resource Advisor 2.2 DSP Resource Reservation 2.3 DSP Usage Graph. 1.1 Overview.
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NS1000 DSP Resources
Contents • 1.1 Overview • 1.2 DSP Resource Capacity • 1.3 DSP Resource Usage • 1.4 DSP Usage – Summary • 2.1 DSP Resource Advisor • 2.2 DSP Resource Reservation • 2.3 DSP Usage Graph
1.1Overview • To digitally process telephone calls, the PBX must use a certain number of DSP (Digital Signal Processing) resources. • DSP resources are provided by the DSP cards installed in the PBX. • Since the DSP resources are limited, no further operations (e.g., telephone calls, playing an OGM) can be performed if all resources are in use. • The following basic operations require DSP resources. • IP extension call (To Trunk) • IP trunk call (To Ext) • Calls via IP-CS (Does not support P2P) • Conferencing • Accessing the Unified Messaging system (including recording calls) • OGM playback • Echo canceller (for trunk-to-trunk analogue calls) • Note. • For IP Ext/Trunk calls, the required DSP resource depends on the codec (Compression) used (G.711 or G.729) . • The Higher the Compression (G.729), the more DSP resource is required (but less Bandwidth) • The Lower the Compression (G711), the less DSP resource is required (but more Bandwidth) • P2P Calls (within the same P2P Group) can be considered NOT to use DSP resources. • DSP Resources are not ‘shared’ between Master/Slave systems – Calculate Resources for each PBX individually.
1.2 DSP Resource Capacity • Each optional DSP card provides a number of resources that can be called upon to provide VOIP processing when the system requires them. • (The NS1000 requires at least 1 DSP card to be installed for it to operate.) • (Up to 2 DSP cards can be installed in each NS1000, therefore the maximum DSP resource available per system is 508) In Addition to the above ‘Free’ Resources, 2 Resources are always reserved for UM Tones – not programmable.
1.3 DSP Resource Usage (1) • The required DSP Resources are calculated using the following values *1 This does not include the DSP cost of the IP-PT/Trunk using the UM Service. *2 Two-Way recording also requires a Conference Trunk
1.3 DSP Resource Usage (2) • IP Phones – “P2P” Call Setup Only P2P Communication DSP is not used at any stage of a P2P call – DSP function is taken care of within handset itself once connected. If selected compression method of phones differs, the handsets negotiate the lowest bandwidth codec of the two: (G729 > G711 > G722) 3. This applies to both SIP and IP-PT types - makes no difference
1.3 DSP Resource Usage (3) • IP-Trunk to IP-Extension DSP Cost 2.2 DSP Cost 1 NS1000 IP-Trunk G.729 G.711 IP-PT From the previous Resource table, we can calculate the DSP Resources required for the above call scenario: 2.2 + 1 = 3.2 DSP Resources Required
1.3 DSP Resource Usage (4) • Unified Messaging Access (MSG Playback) DSP Cost 1 DSP Cost 1.3 G.711 IP-PT UM Recording or playing back messages from the UM requires DSP Resource. For this example, the following DSP Resource is required: 1.3 + 1 = 2.3 DSP Resources Required • Unified Messaging Access (2-Way Rec) DSP Cost 1 + 0.5 IP-PT DSP Cost 2.3 G.711 TBC UM 2-Way Recording requires additional DSP Resource and Conference Trunk. For this scenario, the following DSP Resources are required: 2.3 + 1.5 = 3.8 DSP Resources Required IP-PT
1.3 DSP Resource Usage (5) • Conferencing (Example – 6pty conference). DSP Cost 4.4 (2.2X2) DSP Cost 1 NS1000 DSP Cost 3(6X0.5) IP-Trunk IP-Trunk G.729 (x2) G.711 IP-PT Conferencing DSP Cost 4.4 (2.2X2) DSP Cost 1 TBC Must assign 1 DSP cost for analogue Conferencing. SLT G.729 (x2) A conference requires additional resources to handle multiple voice channels. Also, in standard two-way conversations, analogue lines do not require any DSP resources, but in a conference they do. In addition, IP trunks in a conference require additional DSP resources. For this example the number of required resources are 4.4 + 4.4 + 3 + 1 + 1 = 13.8.
1.4 DSP Resource Usage - Summary • DSP Resource Summary • Accurate DSP selection is only possible when you know the maximum concurrent scenarios that will be required by the system • In most cases, IP phones used in the office will use G722 for extension to extension calls and G711 for ISDN trunk calls so DSPs are used lightly. • Typically only remote IP phones would use G729 mode. (Low Bandwidth) • SIP trunk providers can use either G711 or G729 – available bandwidth on the internet/broadband service will dictate if G711 or G729 is used. • Use the NS1000 DSP Resource tool and Usage graph to guide you to the required DSP card.
NS1000 DSP Resource Advisor
2.1 DSP Resource Advisor (1) • DSP Resource Advisor • The WebMC provides a tool for calculating the number of resources required for given scenarios. • The Installer provides information such as the number of ports/resources required • (e.g., 16 extension ports using the G.729 codec) and the expected load (e.g., 50%busy), and the • resource advisor calculates the number of DSP resources required to meet those conditions. • Example: Call Centre • In a call centre, both the number of trunks and number of extensions required are likely to be high. • Also, since employees are constantly receiving calls, the system load will be high. • Additionally, calls are often recorded at call centers to provide quality-of-service monitoring.
2.1 DSP Resource Advisor (2) • Example: Call Centre (Cont..) • The Web MC DSP Resource advisor can be used to select the necessary DSP combination ‘SETTINGS’ -> PBX Configuration -> 1. Configuration -> 5. DSP Resources -> 1. Setting Select DSP Resource Advisor
2.1 DSP Resource Advisor (3) • Example: Call Centre (Cont..) • Enter the Scenario details; Select the desired DSP combination to give you enough DSP Resource. Check there is sufficient ‘Free’ Resource In this example, it can be seen that both a DSP-L (252) and DSP-S (63) will be required. (Total 315 Available Resources)
2.1 DSP Resource Advisor (4) • Example: Call Centre (Cont..) • It is possible to Apply the necessary DSP Reservation scheme from this scenario also: Recommended Resource Reservation can be applied to the system Click ‘Apply’
2.2 DSP Resource Reservation (1) • Specific resources can be reserved to guarantee a minimum level of service. • Resources reserved for a particular service (e.g., conferencing) cannot be used for another service • (e.g., Unified Messaging). i.e. You may want to reserve resources for OGM (Outgoing Message) to ensure that recorded messages can be played to incoming callers. • The resources can be reserved for the following types of services: • VoIP (G.711) • Conference trunk • Unified Messaging • Two-way Recording • OGM Example NB: UM Tone (required for 2-way recording) is reserved automatically (cannot change)
2.2 DSP Resource Reservation (2) • DSP Resource Reservation Screen ‘SETTINGS’ -> PBX Configuration -> 1. Configuration -> 5. DSP Resources -> 1. Setting Available DSP Resource DSP Resource Reservation + ‘Free’ Resource Select the time to apply the desired reservation Click OK
2.3 DSP Usage Graph • DSP usage graph • The PBX keeps a record of the maximum DSP usage per hour for each of the following features/services. • VoIP (IP trunk, IP extension and IP-CS usage) • Conference • Unified Messaging • OGM • Two-way recording • This data is displayed via the WebMC and shows trends in DSP usage over time, as well as the number of calls / operations abandoned due to lack of resources. (Up to 30 days usage is logged) • The graph allows you to confirm that sufficient resources are available, or if a larger DSP is required. ‘SETTINGS’ -> PBX Configuration -> 1. Configuration -> 5. DSP Resources -> 2. Usage EXAMPLE ONLY! Time Frame